3. Amyloid Beta 42/40 Ratio
A decreased ratio of amyloid beta 42 to 40 in plasma strongly correlates with amyloid plaque accumulation in the brain, a defining feature of Alzheimer’s disease. This biomarker enables early and non-invasive screening for individuals at risk, potentially years before symptomatic onset. Recent studies, including one from JAMA Neurology, highlight its promise as a practical tool for widespread screening and monitoring.